Wind farms typically comprise several wind turbines connected to a grid, which on the one hand transports the produced energy to the consumers and on the other hand provides frequency, voltage and reactive power support. Generally, each wind turbine comprises a wind turbine transformer, a wind turbine converter, a wind turbine generator and auxiliary equipment, e.g. measuring equipment, strobe lights, yaw motors etc.
In case of a lost grid connection the auxiliary equipment has to be provided with power. It may, for example, be important that yaw motors can operate when the grid connection is lost. The yaw motors may, for example, rotate the nacelle of the wind turbine into a position, where the mechanical stresses are minimized. Accordingly, a central wind farm emergency generator is provided, which provides the required active power. However, it is necessary to energize the wind turbine transformers first. Hence, the wind farm emergency generator has to be capable of delivering a high amount of reactive power corresponding to the high inrush current to all of the transformers, too.
So far this problem has been solved by using a relative large diesel generator, which is adapted to deliver the inrush current to the all the transformers. However, in particular in case of offshore wind farms it may be difficult and costly to provide a platform for such a huge diesel generator.
Hence there may be a need for a method for controlling a wind farm, a wind farm controller, a wind farm, a computer-readable medium and a program element allowing for smaller wind farm emergency generators.